Map Function & Map Purpose in Design

TonyG4

Posted 16 April 2010 - 05:02 AM

I have a GIS degree & subsequently 12 years experience in GIS, however the course did have modules in Cartography. I need to edit and design some new maps, so have referenced my old notes.

I am really just after clarification of the terms Map Function & Map Purpose in respect of Cartographic Design.

My understanding of these terms is:

Map Purpose: What the map is for. The cartographer has to consider firstly, what the data is and how much is available (substantive purpose or objective) and secondly, how the map will look, who the end use is and what the map will be used for (affective purpose or objective).

Map Function: The maps function is to communicate information to the map reader. The three classes of map function being 'General Reference Maps', 'Thematic or Special Purpose Maps' and 'Charts'.

I also have notes detailing Map Function as firstly, Invariant Functions which include 'Carrying information' & 'Reflecting an explanation of what is there'. Secondly, Variant Functions which include 'Cognitively creating and/or enhancing spatial knowledge', ' Communication of spatial knowledge to the user', 'Decision support leading to action' and 'Social and behaviour changes related to map use'.

Are these Invariant & Variant Map Functions in a different context and when referring to Map Design I should be considering whether the Map Function will be 'General Reference Maps', 'Thematic or Special Purpose Maps' or 'Charts'?

Also have i got the correct understanding of Map Purpose above?

I hope these two questions make sense and any confirmation on these will be much appreciated.

Map Purpose: What the map is for. The cartographer has to consider firstly, what the data is and how much is available (substantive purpose or objective) and secondly, how the map will look, who the end use is and what the map will be used for (affective purpose or objective).

Map Function: The maps function is to communicate information to the map reader. The three classes of map function being 'General Reference Maps', 'Thematic or Special Purpose Maps' and 'Charts'.

I also have notes detailing Map Function as firstly, Invariant Functions which include 'Carrying information' & 'Reflecting an explanation of what is there'. Secondly, Variant Functions which include 'Cognitively creating and/or enhancing spatial knowledge', ' Communication of spatial knowledge to the user', 'Decision support leading to action' and 'Social and behaviour changes related to map use'.

Are these Invariant & Variant Map Functions in a different context and when referring to Map Design I should be considering whether the Map Function will be 'General Reference Maps', 'Thematic or Special Purpose Maps' or 'Charts'?

I don't believe these terms have anything like universal meanings, and are often used synonymously. These sound like notes from a particular theorist or teacher or textbook writer. Most cartographers tend to keep map theory in the background when we're actually making maps. Useful background, but background nonetheless.

That said, I see a nuanced difference between purpose (or use) and function: purpose implies that the map will be part of a user process—a tool. In a general sense, it implies that the map has a specific role: this map is intended for use in navigation, that one tells you how bad and dangerous our enemies are. Function on the other hand implies thinking of the map as a thing in itself—a machine, as it were. Both important aspects to keep in mind: what a map is for and how it works.

Your discussion of variant and invariant functions sound a little like the analogy to stage and performance I've been using in my work lately.

I think of a chart as specific to a theme that is about real-time spatial phenomena (like a weather chart, or air or water navigation), while a reference map has an exemplar of a country map in an atlas, with no specific designated theme or use.

TonyG4

Posted 23 April 2010 - 06:25 AM

TonyG4

Newbie

Validated Member

5 posts

United Kingdom

Nat Case & Dennis, thanks for your replies.

Dennis, my notes agree with what Nat Case says. The notes describe a chart as a map designed for navigators (e.g. Nautical charts, Coastal charts and Aeronautical charts). They also say that a standard road map is really a chart for land navigation. Whilst my notes say a reference map is a described as a map showing the locations of a variety of different features, such as water bodies, coastlines and roads (e.g. An Atlas or Topographic maps). I think some of these notes were in part taken from one of the suggested course texts we were advised to read at the time (this was around 1995-1996). Hope that helps.

Nat Case, thanks for your comments. I was hoping you would say something like keeping it mind as useful background information, rather than dwelling on it too much. In my previous 12 years I was using GIS systems to produce maps in the engineering sector, generally just using experience and getting what I felt was the right 'look' of the maps & plans for the engineers.

Now that I am doing some new work which is much more about the cartography side of things, I wanted to get opinions from people as to cartographic design in day to day work.

I have had a look at your link to the 'stage and performance' too.

Overall, from what I understand you have said, we basically should consider cartographic theory in the background only, then produce what we feel looks right, but also considering who the type of user is and what they will be using the map for.